Navigation presents a perennial challenge for visually impaired persons. Without the ability to rely on sight, obstacles and goals alike are more difficult to find. The art of wayfinding, or navigating, orienting oneself in, and using physical space, requires constant learning and innovation, and has given rise to a number of techniques used in concert. On sidewalks and in other areas designed for frequent travel, such as hallways, it is often possible to feel the way by touching railings and walls, and using aids such as white canes to search the ground for guides and hazards. In familiar environs, such as the home or office, memory can serve as a primary guide, as the visually impaired person follows a mental map he or she has formed through familiarity, with aids such as the white cane serving in a supplemental role to discover unexpected obstacles. Some combination of feeling the way and memory can be used to explore most areas in time, but the existing methods often fall short in unfamiliar spaces that require more complex interaction, such as public bathrooms. It can be awkward and slow to find a sink or a bathroom stall by feel, and the layout of such spaces are not sufficiently predictable for navigation by guesswork.